A particle starts from origin at t=0 with velocity `5.0hati m//s` and move in x.y plane under action of a force which produces a constant acceleration of `(3.0hati+2.0hatj) m//s^(2)`. (a) What is the y-coordinate of the particle at the instant its x-ccordinate is 84 m? (b) What is the speed of the particle at this time?